Transcript 4361726469616320537572676572792049

CARDIAC SURGERY I
Outline
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Heart A & P
CAD
Open Heart Diagnostics
Anesthesia and Medications on Field
Open Heart Patient Preparation
Supplies, Instrumentation, and Equipment
CABG
Complications of CABG
Congenital Pathologies of the Heart
Cardiac Arrhythmias: Pacemakers and AICDs
Anatomy of the Heart
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Four chambers:
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Upper atria x 2
Lower ventricles x 2
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Four valves:
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Atrioventricular valves x 2
Semilunar valves x 2
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Divisions:
ventricular and
atrial septum
separate each atria
and ventricle
Coronary sulcus
separates atria
from ventricles
Heart Anatomy
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Beneath the sternum is a layer of fat or
subcutaneous tissue that must be dissected
to get to the mediastinum (cavity between
the pleural cavities)
Through the mediastinum is a shiny sac that
will be opened to expose the heart
This is the “PERICARDIUM”
In the pericardium is a serous lubricating
fluid that protects the outer layer of the heart
(as it is constantly moving) called the
“EPICARDIUM”
Heart Anatomy
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The muscle layer or middle layer of the
heart is the MYOCARDIUM
The inner layer or lining of the heart is
called the ENDOCARDIUM
Endocardium is a continuous layer
with the blood vessels
Normal Circulation
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Blood comes back to heart for reoxygenation via
SVC and IVC entering the RA>tricuspid valve>RV>
pulmonic valve into the pulmonary trunk>R/L
pulmonary arteries>Lungs (reoxygenated)>returns
to heart via the pulmonic veins (two per side/four
total) into the LA>mitral (bicuspid)valve LV through
the aortic valve pushing oxygenated blood into the
aorta and coronary ostia as it passes them through
the aortic arch and throughout the rest of the body
where oxygen is needed by all the organs and
tissues
Coronary Anatomy and
Circulation
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Coronary Ostia are the origin points of
coronary (heart) circulation
Right and Left on either side of the aorta just
above the aortic valve
Left coronary “left main” bifurcates into the
LAD (left anterior descending) and the Cx
(circumflex)
Diagonal branches come off the LAD
OM (obtuse marginals) come off the
circumflex
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LAD and circumflex branches supply
oxygen to the anterior and posterior
portion of the heart which involves
important structures such as bundle
branches, papillary muscles of the
mitral valve, and in 50% of patients,
the SA (sinoatrial node)
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Right coronary artery bifurcates into the right
coronary artery and posterior descending coronary
artery (PDA)
The right coronary artery can have branches called
marginals
The right coronary artery supplies blood to the right
atrium and in 50-60% of patients, the SA node
The PDA supplies blood to the posterior ventricular
septum, half the inferior wall of the left ventricle,
papillary muscles of the mitral valve and the AV
(atrioventricular) node
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Coronary arteries ultimately drain (as
coronary veins) into the coronary
sinus, located in the right atrium where
the vena cava also empty after oxygen
has been used by its respective
organs so that the reoxygenation
process may start all over again
Cardiac Conduction
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Coordinates cardiac conduction
SA Node (sinoatrial) “the pacemaker”
AV Node (atrioventricular)
Bundle of HIS or AV Bundle
Down R/L insulated branched bundles
in ventricular septum
Purkinge Fibers non-insulated and
feed into R/L ventricles
Cardiac Conduction
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SA node initiates impulse > atria contract
(blood forced into ventricles)> stimulus
picked up by AV node > AV Bundle (signal
slightly delayed) > brnached bundles >
purkinge fibers > ventricles stimulated and
contract (blood forces atrioventricular valves
to close and semilunar valves to open)
These valves should go one-way
Cardiac Cycle
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Two phases:
Diastole
Systole
Cardiac Cycle
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Diastole
2/3 cardiac cycle
Ventricular relaxation
Ventricles fill with blood
AV valves open (tricuspid and mitral)
Pressure higher in atria creating
ventricular filling
Cardiac Cycle
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Systole
1/3 cardiac cycle
Atrial contraction
Blood pumped to ventricles filling pulmonary
and systemic arteries
With volume of blood in ventricles,
ventricular pressure greater than atrial
Mitral and tricuspid valves shut
Ventricles contract, blood pushed into
pulmonic and aortic valves
Cardiac Cycle
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4-6L of blood pumped throughout body
per minute
This total volume = cardiac output
CO=SV (volume of blood in each
systole) x R (number of beats per
minute)
Heart Sounds
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Closure of the AV valves (tricuspid and
mitral) = 1st heart sound S1 = start of
systole
Closure of semi-lunar valves = second
heart sound S2 = start of diastole
Parasympathetic and
Sympathetic Nervous System
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Nerve fibers from PSNS and SNS
originate in medulla oblongata end in
SA and AV nodes
PSNS fibers slow heart using
acetylcholine
SNS fibers raise heart rate using
norepinephrine
Coronary Artery Disease
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Coronary Heart Disease is the number one
cause of death in the United States
Risk factors for coronary heart disease
include: cigarette smoking, hypertension,
elevated cholesterol, lack of physical
activity, diabetes, obesity, reproductive
hormones, type A personality traits, and
heredity
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Coronary Heart Disease (CHD) is defined as
“myocardial impairment due to an imbalance
between coronary blood flow and
myocardial oxygen requirements”
CHD is primarily caused by atherosclerosis,
a narrowing or occlusion of the coronary
arteries=Coronary Artery Disease (CAD)
CHD can be related to blood clots or arterial
spasm
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Atherosclerosis most often occurs in the
proximal segments of the coronary arteries
This is a fortunate circumstance as it makes
surgical revascularization techniques
possible and effective
Without myocardial blood supply,
myocardial infarction (MI) or heart attack
occurs, and life is threatened
Coronary Artery Bypass Grafting
CABG
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Surgical revascularization technique
Other options depending on the severity of disease
are coronary balloon angioplasty (PTCA),
atherectomy, ablation, and stent placement (These
procedures are done in the cardiac catheterization
lab)
CABG is literally providing the patient with a “new”
coronary artery which bypasses or goes around the
existing stenosis creating a new origin point on the
aorta for that artery, resupplying an area of the
heart with blood that is otherwise limited
Diagnosis
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NONINVASIVE
H&P
ECG/EKG
Exercise EKG or Stress Test
Chest X-ray
Diagnosis
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INVASIVE
Aortography
Electrophysiology (EP) studies
Cardiac catheterization-provides
definitive information for ischemic or
coronary artery disease
Endomyocardial biopsy
Sequence of Events
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Room set-up
Furniture
Equipment
Personnel in the room
Anesthesia
Graft Harvesting by the PA
Greater Saphenous vein
Radial Artery
Equipment
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Two large tables (back table and Mayfield)
Mayo stand (for saw)
Double ring
Prep tables x 2
Slush machine/warmer
ECU x 2
Cell saver
CPB machine
Off-table suction
Video tower if doing ESVH (insufflator, camera, light source,
video monitor)
External pacing box to CRNA
Instrumentation
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Open heart trays
IMA Retractor
Delicate Tray if doing radial harvest and an (extra) smaller
back table like we use in lab
Micro instrument set
Doctor specials micro instrument set
Sternal retractor (Ankinney)
Finochetti
Sternal saw
Internal defibrillator paddles (size is surgeon preference)
standard size is 6.0
ESVH Tray
Supplies
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CV Drape pack
Coronary custom pack
Three quarter sheets x 3
Gloves for all involved in surgery
Miscellaneous suture (silk ties (4-0, 3-0, 2-0, 0, 1, 2), pericardial,
cannulation, distal anastamoses, proximal anastamoses, pacing
wires, suture to sew in pacing wires (surgeon dependant), cutting
needles to sew in chest tubes and pacing wires to skin, sternal wires,
fascia, subcutaneous, subcuticular
Will also need closing suture for the PA to close the leg incision or
radial incision on the arm (subcutaneous and subcuticular)
If using the femoral artery or vein may need appropriate sized
prolene to close the vessel after cannuli are removed
If using same saphenous vein that goes to the femoral vein
cannulated, will simply tie off that femoral vein after cannula is
removed
Supplies continued
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Chest tubes of surgeon choice (need chest tube for side that IMA is
being harvested, a mediastinal chest tube, and a substernal chest
tube)
Aortic punch
Graft markers
Clips (small, medium, and large)
Small suction to suction the chest tubes before hooking up (10F)
Arterial cannula, venous cannula, antegrade cannula, medusa,
vessel cannulas, retrograde cannula
Y-connectors for chest tubes
Straight connector for venous if it is not on it (must know size of
pump tubing and cannula end
Coronary suction or blower mister
Intracoronary shunts if “beating” or OPCAB
Supplies
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Special retractor for OPCAB or “Beating”
(called Guidant stabilizer system or
Medtronic’s: octopus, starfish, or urchin
stabilizing systems (surgeon choice)
Temperature probe/Foley
Myocardial temperature probe (optional)
Cardiac insulation pad
Drugs on Field
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Warm Saline with antibiotic if surgeon preference (Ancef)
Cold Saline
Cardioplegia Solution
Papaverine 60mg/2ml + 30ml of PF NS
Sternal hemostatic (bonewax or combination of gelfoam
powder and thrombin or saline)
Gelfoam sponge (may cut to anastamosis size)
Avitene
Surgicel
Heparinized LR or NS for the vein soak/prep
Combination of albumin, 10ml of papaverine mix, and 30cc of
heparin saline for radial artery soak
Patient Positioning
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Supine
Arms tucked/padded (esp. side IMA
bar will be on) aware of arterial line
impediment
Headrest
May use pillow under knees or gel
pads for heals
Prep
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Betadine soap followed by betadine paint
Some places use spray or gel betadine
Begin at sternum and work your way out to groins, then pubis
last
May proceed from groins to lower legs
Proper procedure is to do the upper body separate then wash
each leg individually beginning at the leg incision site and
working your way out circumferentially, always prepping the
pubis last
Will do at least two coats of paint after the soap has been
done by the circulator
May or may not do feet depending on the institution (if do not
prep as far to lower ankle as possible and get under the lower
legs to lower buttock
Draping
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Groin Towel (tri-folded, long way)
Towels x 2 on either side, neck towel
(secure with towel clips or staples)
Lower leg drape, should have adhesive strip
Wrap feet with towels x 2 and kerlix or
booties if have been prepped
Drying towels
X-large IOBAN
CV Drape
Sequence of Events
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Greater Saphenous vein harvest
simultaneous with mediansternotomy
Mediansternotomy
Internal Mammary Artery Harvest (IMA)
Cannulation for CPB
Aortic cross clamp applied
Cardioplegia administered
Temp reduced
Heart stopped
Cardiopulmonary Bypass
CPB
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Procedure done to stop the heart and empty
the heart of blood temporarily so that the
heart is protected and a bloodless field is
provided for optimal visibility by the surgeon
Are newer methods available to not stop the
heart (OPCAB)
An example of someone who would not be
receptive to CPB would be someone at risk
of a stroke (existing carotid stenosis)
CPB
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Heparin given before CPB to prevent coagulation
Hemodilution done by anesthesia to decrease blood viscosity and
prevent clotting
See diagram: purse string sutures are placed on the aorta x 2, on
the right atrium x 2, and later on the aorta x one below where the
aortic cannula is placed
An aortic cannula is placed into the aorta and attached to the arterial
CPB tubing
A Venous cannula is placed in the right atrium into the inferior vena
cava and attached to the venous CPB tubing
A retrograde cannula is placed into the coronary sinus via the right
atrium attached to a pressure line which is monitored by anesthesia
and a cardioplegia line which goes to the perfusionist
An antegrade cannula/vent is placed into the aorta below the arterial
cannula which is attached to the cardioplegia line and a vent line
going to the perfusionist
Protecting the Heart
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Patient core body temperature is reduced ≤ 30°
Heart temp is reduced ≤ 12°
Cardioplegia is a high potassium solution that stops and
protects the heart
The antegrade and retrograde lines allow for cardioplegia to
be administered by the perfusionist directly into the heart
Antegrade sends cardioplegia directly into the coronary ostia
protecting those areas of the heart above the coronary
stenoses
Retrograde sends cardioplegia in reverse to protect the areas
of the heart below the stenoses
Depending on severity of the disease as well as surgeon
preference, retrograde may not be used
Protecting the Heart
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Before cardioplegia is administered an aortic cross clamp is
placed between the arterial cannula and antegrade cannula to
prevent blood circulating through the arterial cannula from
coming into the heart as well as prevent cardioplegia from
going into the patient’s bloodstream
Blood that comes through the superior vena cava that may not
be picked up by the venous cannula to go to the CPB machine
can be sucked out of the heart through the vent attached to
the antegrade line so that it can be added to the CPB circuitry
Hence you have mechanical cardiopulmonary bypass of the
patient’s normal cardiopulmonary bypass
We’re ready to GRAFT some new coronaries!
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Distal anastamoses
Rewarming/Restarting the heart
Cardioplegia cessation
Warming Patient with CPB circuitry
Administration of Lidocaine (PRN)
Defibrillation (PRN)
Temporary Pacing (PRN)
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Proximal anastamoses
Decannulation “Coming Off Bypass”
Pacing wires/Chest tubes
Drying up
Closure
May close the pericardium with pop-off neurolon or silk sutures
especially if anticipating a re-operation or if patient is very young
Sternal wires
Fascia
Subcutaneous
Subcuticular
Dressing
Patient to CVICU
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CABG animation
IABP
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Intra-aortic balloon pump
Sometimes a patient’s heart does not regain
its normal pumping ability after coming off
bypass. In these instances, an IABP will be
placed to assist the patient’s heart so that it
may regain its normal pumping function
gradually.
Patient’s requiring these can usually be
anticipated by their poor cardiac function
and disease at the beginning of the
procedure
RE-DO Heart Surgeries
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If this is a second heart procedure will need an
oscillating saw and anticipate crashing on bypass if
injury is sustained upon opening of the sternum
Scar formation/Adhesions of result in heart
structures adhering to the sternum making them
susceptible to being injured with mediansternotomy
Generally femoral cannulation for CPB is used in
these circumstances to avoid such an event
allowing patient to be ON BYPASS before the
sternum is opened
Complications
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Cardiogenic shock
PE (pulmonary embolus)
Myocardial contusion
Mechanical venous obstruction
Hypothermia
Cardiac tamponade (pericardial sac fills with
blood = pressure on heart)
Arrythmias
Infection
Congenital Pathology
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PDA
ASD
VSD
Tetrology of Fallot
Coarctation of the Aorta
PDA
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Patent ductus arteriosus
Channel joining PA or pulmonary artery to
aorta in utero remains patent
Normally closes within hours after birth
Asymptomatic in early childhood, growth
and development are normal
Symptoms progress: Thrill palpable in
upper left sternum and continuous murmur
heard in systole and diastole (machine-like)
ASD
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Atrial septal defect
Atrial septum opening
Results in shunting of blood from left to right
atrium, increasing pulmonary blood flow
Tolerated
Symptoms rare in infants
Normal development
Symptoms in children and young adults are
fatigued and DOE (dyspneic on exertion)
VSD
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Ventricular septal defect
Ventricular septal opening
Primarily subaortic
Size and position vary
Small are asymptomatic
Large defects create slow birth weight and
growth
Severe creates heart failure
Tetrology of Fallot
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4 components:
Pulmonary valve stenosis
VSD
Hypertrophy of right ventricle
Over-riding aorta
Results in blood being shunted away from pulmonary system
decreasing oxygenated blood delivery to systemic system
Symptoms: cyanosis with exertion (crying ) then at rest,
delayed development
Repaired prior to school-age
Good prognosis
Coarctation of Aorta
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Severe narrowing of descending aorta at ductus
arteriosis junction and aortic arch below or distal to
left subclavian artery
Result is left ventricle workload increase
May be concurrent with PDA and VSD
Diagnosed first months of birth with development of
heart failure in infants with concurrent disorders
Asymptomatic , growth and development are
normal
Diagnosed accidentally with BP findings
Teens may complain of lower extremity cramping
that worsens with exercise
Cardiac Arrythmias or
Dysrhythmias
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Abnormal heart rhythm
Causes:
Heart disease, drugs, trauma
Heart block or sinus bradycardia are indications for a pacemaker
insertion
Treatment:
Pacemaker insertion
Pacemaker consists of a generator (produces electrical impulses)
and leads that carry electrical impulses to electrodes which are
placed in the atrial or ventricular endocardium where ever impulse is
lacking at SA or AV node (unipolar) or both (bipolar)
Impulse does not emit unless heart rate falls below pre-set level
Lithium battery in generator lasts several years (around ten)
Pacemakers
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If surgical patients are know to have a pacemaker,
avoid ECU
Creates electromagnetic interference
If must use, place dispersive electrode on thigh or
as far away from generator as possible
EOL (end of life) of battery or generator most
common reason for replacement
Newer models have a metallic shield that minimizes
the original concern of household appliances
affecting the device
AICD
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Automatic implantable cardioverter- defibrillator
Recognizes life-threatening cardiac dysrhythmias such as
ventricular tachycardia or ventricular fibrillation
Generator set to recognize and “shock” or convert arrhythmia
to normal rhythm
Newer models can pace and defibrillate
ESU or MRI can deprogram AICDs or ICDs creating random
electrical discharges onto the myocardium
“Magnets” or electromagnetic wands can be used to
deactivate the device prior to surgical incision and be used to
reactivate and reprogram the device
AICDs are not affected by household appliances
Summary
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Heart A & P
CAD
Open Heart Diagnostics
Anesthesia and Medications on Field
Open Heart Patient Preparation
Supplies, Instrumentation, and Equipment
CABG
Complications of CABG
Congenital Pathologies of the Heart
Cardiac Arrhythmias: Pacemakers and AICDs